I'm in the same boat with you Grim, I just switched this week from BC to Advanced. I talked with the hydrostore owner for about an hour about the different ones and what i'll need/want for optimum growth.
For now I settled on Sensi A + B, Sweet Leaf, Carbo Load, and Voodoo juice. I'm in the first week of veg as of 2 days, and I'm going to go back to get more additives just before I start flowering. Those will probably be Big Bud, Bud Blood, Overdrive.
I'm also currently using hygrozyme in conjunction with the advanced nutes. And once flower has begun I'm going to give Atami's Bloombastic a try as i've heard really good things about that.
I got quarts of most eveything for now as I just wanted to test it out and the gallons were pretty pricy. So far so good, but only a few days in. I did notice however that the voodoo juice (very pricy, but only used every 3 weeks) was the one I used the most of at just under 1oz/1gallon mix, the others were not to bad at all though. I know it's gonna be more pricy than my previous BC mixture, but i'm willing to drop a buck if I see results I like.